So you will have to create a choice to choose between male or female love interests first, then add gains inside those choice options. Then you will have to create 2 different branches in each chapter.
NARR
What is your dating preference?
choice
“I like boys” {
gain dateboys
} “I like girls” {
gain dategirls
}if (dateboys) {
goto dateboys_branch} else {
goto dategirls_branch
}label dateboys_branch
[story line for boy love interest goes here]
goto end_storylabel dategirls_branch
[story line for girl love interest goes here]
goto end_storylabel end_story
[end of the chapter goes here]
Then each chapter after the first, just continue doing what is in bold.